A tool assembly includes an ultrasonic blade and a jaw member. The ultrasonic blade includes a proximal portion and a distal portion. The distal portion extends from the proximal portion and defines a longitudinal axis. The distal portion is configured to oscillate along the longitudinal axis to ultrasonically treat tissue. The distal portion includes a top portion, a bottom portion, a notch, and planar side segments. The notch is disposed on the bottom portion. One of the top portion, the bottom portion, or the notch is configured to dissect tissue. The top portion is configured to seal tissue. The jaw member is configured to move relative to the ultrasonic blade and is configured to contact the top portion.
